burton



(No Model.)

G. D. BURTON & E. E. ANGELL. ELECTRIC BATH METAL HEATING APPARATUS.

No. 537,402. Patented Apr. 9, 1895.

w/f f 6L UNITED STATES PATENT Orrrcn.

GEORGE D. BURTON, OF BOSTON, AND EDWIN E. ANGELL, OF SOMERVILLE,MASSACHUSETTS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO SAID BURTON.

ELECTRIC-BATH METAL-HEATING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 537,402, dated April 9,1895.

Original application filed September 5, 1892, Serial No.445,148. Dividedand this application filed October 11, 1894. Serial No.

To all whom it may concern:

Be it known that we, GEORGE DEXTER BUR- TON, residing at Boston, in thecounty of Suffolk, and EDWIN ELLIOTT ANGELL, residing at Somerville, inthe county of Middlesex, in the State of Massachusetts, citizens of theUnited States of America, have invented certain new andusefullmprovements in Electric- Bath Met-al-I-leating Apparatus, ofwhich the following is a specification.

This invention relates to the art of working metal for forging or othermetal working operations by immersing the metal or that portion thereofto be heated in a bath and passr5 ing therethrough an electric currentof such a character as to cause the formation of an incandescent gasenvelope or electric are at or below the surface 01 the solution andaround the metal to be heated, whereby the heating thereof is quicklyeffected.

The invention consists in certain'apparatus substantially as hereinafterdescribed and claimed for the convenient and rapid carrying out of theprocess.

Figure l of the accompanying drawings represents a vertical transversesection of a tank for containing the electric bath and a holder forsupporting rivets to be heated therein, said tank and holderconstituting a 0 part of this apparatus. Fig. 2 represents a verticalsection of a tank constituting a part of this apparatus and containingan electrolytic bath, this figure illustrating a metal bar in the act ofbeing-heated in said bath. Fig. 5 3 represents a longitudinal section ofa rivet holder for supporting rivets to be heated by this apparatus.

The same reference numbers indicate the same parts in all the figures.

A tank 70 contains a solution 74 of equal parts of sal-soda and cream oftartar ot' the specific gravity of 1.255 at 77 Fahrenheit, or

. a solution of any other suitable liquid may be employed, preferably asolution containing a 5 chemicalsalt. The solution should be one,

however, which is capable of developing hydrogen gas around the metalwhile being heated, either by the accumulation of the gas bydecomposition of the fluid by electrolysis (No model.)

around the heated metal, or by the deposit of the hydrogen from theopposite electrode around it While the heating process is going on. Thistank is provided with a vertical porous partition 73 which permits thepassage of the electric current and prevents the positive plate fromcoming into contact with the work. A positive plate 71 is disposed inthe tank 70 and connected by conductors with the positive pole of anelectric source. The tank is provided on its side with the rest 75 63for supporting the work or work-holder, said rests comprising a bar ofinsulated material attached by brackets to the side of the tank.

A Work-holder 90, shown in Fig. 3, as adapted for holding rivets to beheated, comprises 65 an insulated handle 91 and a bar 92 having holesfor receiving the rivets, said holes being surrounded by collars or rims95.

In the use of the apparatus shown in Fig.

l, the current passes from the positive pole of the electric sourcethrough the conductor 60 to the positive plate 71 in the tank 70, thenceinto the solution in said tank and through the porous partition 73,thence from said solution to the work, as 100, supported 75 in thework-holder 80. In passing from the liquid to the work, an arc is formedbelow the level of the solution around said work, or the portion thereofto be heated. The current then passes through the work-holder and thencethrough the conductor 61 to the negative pole of the electric source.The voltaic are formed around the work, tends to quickly heat said work,and when the'forging temperature is reached, the work-holder iswithdrawn 8 5 from the tank.

The partition 7 3 in the working tank serves to prevent contact of thework or work-holder with the positive plate 71 and avoids a shortcircuiting of the current. The polarity may be reversed in this case ifdesired.

In the process of electric bath metal working carried out by thisapparatus, the solution itself may be said to constitute one of theelectrodes, and being flexible it surrounds 9 5 the bar to be heated andan are or luminous film is formed around all the submerged partsthereof, whereby said bar is uniformly heated throughout. The work,constituting the nega tive electrode, offers a much higher resistancethan the other metallic electrode or anode and while the are is formedbetween the work and the liquid electrode, the current passes from theliquid electrode to the positive metallic electrode withoutincandescence or luminosity.

The advantages of heating the metal by this means are its entireexclusion from oxygen or other deleterious gases during the operation,whereby the metal is left in a clean state ready for forging and weldingwithout the use of fluxes to counteract the effects of oxidation. If theprocess of heating is conducted with a proper current and with theelectrodes at the proper distance apart, the hydrogen set free at theelectrodes accumulates around the metal being heated, and opposes thepassage of the current with such resistance as to itself becomeincandescent as may be readily seen by looking down into the fluid,while a constant stream of these hydrogen bubbles should be visiblepassing between the electrodes and surrounding the metal. Theincandescent hydrogen is thus made to reinforce the direct action of theheating current and it will even be found that the heating of themetaliu this way will clean off the oxidation on the surface of themetal when the pro cess began. This, for example with the rivets shown,enables them to make a better and closer job of riveting than otherwise.

Fig. 2 shows a tank in which the work-rest constitutes the negativeterminal, the bar of said rest being composed of conductive instead ofinsulated material and being connected with the conductor 61. Thisconductive rest is adapted for heating bars or pieces of metal, as 200,which are held in contact with or permitted to lie against saidconductive rest, with their lowerends projectinginto the liquid in thetank. In this case the current passes from the tank liquid into the endsof the bars submerged therein forming an are around the same. The areformed quickly heats the bars to a forging temperature. The currentpasses up through the bar into the rest and thence through the conductor61 to the negative conductor of the electric source.

In this case the positive plate is shown as provided with a shank 71which projects through the wall of the tank being connected with theconductor 51 outside of the tank.

The tank is preferably portable, and is very convenient for the heatingof rivets for boiler makers and for other purposes, as it can be quicklyand easily moved about where the work is being done.

This application is a division of our application, Serial No. 445,148,filed September-5, 1892.

We claim as our invention- 1. A portable tank for heating metalsprovided with,,a porous partition and with a bracket at one side servingas a rest for the work or work-holder.

2. A portable tank for heating metals provided with a porous partitionand with a bracket at one side serving as a rest for the work-holder,said rest constituting one terminal of the tank.

3. A movable work-holder connected with an electric conductor andprovided with an insulated handle and with holes for holding the metalto be heated.

4. A movable work-holder connected with an electric conductor andprovided with an insulated handle and with holes for heating the metalto be heated, said holes being surrounded by raised rims.

5. A portable tank for heating metals provided with electric connectionsand with a bracket at one side which serves as a rest for the Work saidrest constituting one of the electric terminals of the tank.

GEO. D. BURTON, EDVIN E. ANGELL.

Witnesses:

W. D. EATON, J. A. STROUT.

